Continuous casting facility, and operation and maintenance method of continuous casting facility

Abstract

To perform a dummy bar preparation work and a maintenance work of a cutting device in parallel without dividing time in a continuous casting facility.SOLUTION: A continuous casting facility includes a slab production line comprising a plurality of segment rolls and a plurality of table rolls, and a cutting device for cutting a slab into a predetermined length. In the continuous casting facility, a dummy bar intrusion prevention device is arranged between the last segment roll arranged most downstream of the plurality of segment rolls and the cutting device. The dummy bar intrusion prevention device includes an impact absorbing part capable of moving up and down with respect to a path line in the cutting and conveying zone of the slab production line.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a continuous casting facility having a dummy bar and a cutting device. [Background technology]

[0002] In continuous casting equipment, molten steel stored in a mold is solidified through a tundish, and the resulting slab is then continuously drawn downstream by a group of segment rolls. At the start of casting, the bottom opening of the mold is blocked by a dummy bar, and after molten steel is poured into the mold and solidified, the slab is drawn out while engaged with the dummy bar. Therefore, it is necessary to insert the dummy bar into the mold before casting begins.

[0003] In general, in a continuous casting facility, before the start of casting, work is performed to check that the dummy bar is operating normally from insertion to withdrawal (hereinafter also referred to as "dummy bar preparation work"). The dummy bar preparation work refers to a series of work that includes withdrawing the dummy bar, which is inserted into the opening of the mold and held by the group of segment rolls, downstream, and confirming that the dummy bar is supported and guided smoothly through the in-machine casting zone and has passed the last segment roll, and then hoisting and recovering the dummy bar with a wire rope or the like. Here, the in-machine casting zone refers to the area through which the cast strip or dummy bar passes, from the top end of the mold 4 to the last segment roll 5a in Fig. 1.

[0004] Patent Document 1 proposes a dummy bar carriage fall prevention device in which a fixing metal fitting and a stopper are attached to the wire rope. The fall prevention device of Patent Document 1 can prevent the dummy bar from falling even if the wire rope breaks during retrieval of the dummy bar. Patent Document 2 proposes a dummy bar insertion device for continuous casting equipment that can smoothly support and guide the dummy bar and transfer the weight of the dummy bar during casting preparation. The dummy bar insertion device of Patent Document 2 is structured so that the load when inserting the dummy bar into the mold is supported not only by the pinch rolls but also by the stopper inside the dummy bar insertion device, so there is no need to increase the support force of the pinch rolls and the dummy bar can be inserted smoothly. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 59-025349 [Patent Document 2] Japanese Unexamined Patent Publication No. 50-121128 Summary of the Invention [Problem to be solved by the invention]

[0006] However, inventions such as those shown in Patent Documents 1 and 2, which prevent the dummy bar from falling during the dummy bar retrieval operation or support the load during the dummy bar insertion operation, were not able to prevent the dummy bar from falling after the dummy bar is inserted, and improvements were required.

[0007] Specifically, if the dummy bar held by the segment rolls in the in-machine casting zone slips down the in-machine casting zone for some reason after the above-mentioned dummy bar preparation work, it may reach the installation position of the cutting device (a device that cuts out the cast strip to a specified length) in the cutting and conveying zone downstream of the line. Therefore, if maintenance work on the cutting device is performed in parallel with the dummy bar preparation work, there is a risk that the maintenance work will be hindered by the dummy bar that has entered the cutting and conveying zone. For this reason, in the past, the dummy bar preparation work and the maintenance work on the cutting device in a continuous casting facility were performed at separate times to prevent the two works from interfering with each other.

[0008] However, if the dummy bar preparation work in the continuous casting equipment and the maintenance work for the cutting device are performed separately in terms of time, the downtime of the continuous casting equipment will be extended, which may result in a decrease in productivity.

[0009] In view of the above, the present invention aims to provide a continuous casting facility in which the dummy bar preparation work and the cutting device maintenance work can be performed in parallel without dividing them into periods. Note that the problems and the purpose of use of the facility in Patent Documents 1 and 2 are completely different from those of the present invention. [Means for solving the problem]

[0010] In order to solve the above problems, the continuous casting equipment of the present invention is (1) a continuous casting equipment including a slab production line formed of a plurality of segment rolls and a plurality of table rolls, and a cutting device that cuts the slab to a predetermined length, wherein a dummy bar entry prevention device is disposed between a final segment roll that is located most downstream among the plurality of segment rolls, and the cutting device, and the dummy bar entry prevention device is equipped with an impact absorbing section that can be raised and lowered relative to a pass line in a cutting and conveying zone of the slab production line.

[0011] (2) In the above configuration (1), the shock absorbing portion can be realized by a crushable structure that plastically deforms during a collision to absorb impact energy.

[0012] (3) In the above configuration (2), the crushable structure can be realized by a hollow structure having a large number of hollow portions.

[0013] (4) In the above configurations (1) to (3), the dummy bar intrusion prevention device is characterized in having a mechanism for raising and lowering the impact absorbing portion relative to the pass line.

[0014] (5) An operation and maintenance method for a continuous casting equipment described in any one of (1) to (3) above, in which, with the shock absorbing part raised relative to the pass line, a dummy bar preparation work for checking the operation of inserting and extracting a dummy bar and a maintenance work for inspecting and repairing the cutting device are performed in parallel.

[0015] (6) An operation and maintenance method for the continuous casting equipment described in (4) above, in which, with the shock absorbing section raised relative to the pass line, a dummy bar preparation operation for checking the insertion and withdrawal operation of the dummy bar and a maintenance operation for inspecting and repairing the cutting device are performed in parallel. Effect of the Invention

[0016] According to the present invention, the dummy bar preparation work and the cutting device maintenance work in the continuous casting equipment can be performed in parallel without dividing the time. By performing these works in parallel, the downtime of the continuous casting equipment can be shortened, and the productivity can be improved. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a side cross-sectional view that shows a schematic configuration example of the continuous casting equipment 1 according to the present embodiment during casting. [Diagram 2] FIG. 2 is a side cross-sectional view that illustrates an example of the configuration of the continuous casting equipment 1 according to the present embodiment during a dummy bar preparation operation. [Diagram 3] 2 is an enlarged view of an area P surrounded by a dashed line in FIG. 1. [Figure 4] FIG. 3 is an enlarged view of an area Q surrounded by a dashed line in FIG. [Diagram 5] FIG. 4 is a view taken along the line AA in FIG. [Figure 6] FIG. 2 is a plan view of a shock absorbing section having a tile structure. [Figure 7] FIG. 4 is a plan view of a shock absorbing section having a mesh structure. [Figure 8] FIG. 2 is a plan view of a shock absorbing portion having a honeycomb structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Configuration of continuous casting equipment 1> First, a continuous casting equipment 1 in this embodiment will be described with reference to the schematic diagrams of the continuous casting equipment in Fig. 1 and Fig. 2. Fig. 1 corresponds to the time of continuous casting, and Fig. 2 corresponds to the time of dummy bar preparation work. The continuous casting equipment 1 in this embodiment includes a ladle 2, a tundish 3, a mold 4, a plurality of segment rolls 5, a plurality of table rolls 6, a cutting device 7, and a dummy bar intrusion prevention device 8. The segment rolls 5 are indicated by black circles, and the table roll 6 is indicated by a white circle (the same applies to Figs. 3 and 4).

[0019] Molten steel taken out from the refining system is supplied to the ladle 2. The molten steel supplied to the ladle 2 is poured into the tundish 3 through a nozzle extending from the ladle 2. The ladle 2 and the tundish 3 can be called a molten steel supplying device. The mold 4 is formed of a water-cooled copper plate, and casts the molten steel poured from the tundish 3. Downstream of the mold 4, a slab production line L is formed in the continuous casting facility by a plurality of segment rolls 5 and a plurality of table rolls 6. The slab production line L includes an in-machine casting zone L1 formed by the mold 4 and the segment rolls 5 downstream of the mold 4, and a cutting and conveying zone L2 formed by a plurality of table rolls 6 and a cutting device 7. The slab drawn out from the lower end opening of the mold 4 is cooled while being supported and guided by the segment rolls 5, and is conveyed to a cutting position in the cutting and conveying zone L2 by the table rolls 6. The slab that reaches the cutting position is cut to a predetermined length by the cutting device 7. The cutting device 7 may be a hydraulic shear, a gas cutter, or the like.

[0020] The white arrow in Fig. 2 indicates the direction of movement of the dummy bar 40 during the dummy bar preparation work. As described in the "Background Art", in a typical continuous casting facility, the dummy bar 40 inserted into the lower end opening of the mold 4 and held by the segment rolls 5 is pulled downstream as a dummy bar preparation work before the start of casting, and after it is confirmed that the dummy bar 40 is supported and guided smoothly through the in-machine casting strip L1 and has passed the final segment roll 5a, the dummy bar 40 is lifted up and retrieved by a wire rope or the like (in other words, the operation of the dummy bar 40 is confirmed) (the dashed line portion in Fig. 2). The retrieved dummy bar 40 is inserted again into the lower end opening of the mold 4. However, after this dummy bar preparation work, the dummy bar 40 supported by the segment roll 5 may not be guided properly and may slide down along the in-machine casting strip L1, and the sliding dummy bar 40 may enter the installation position of the cutting device 7. In this specification, the dummy bar preparation work and the cutting device maintenance work are collectively referred to as the "operation maintenance method for continuous casting equipment."

[0021] Therefore, the continuous casting equipment 1 of this embodiment is provided with a dummy bar intrusion prevention device 8 to prevent the dummy bar 40, which has slid down along the in-machine casting strip L1, from intruding into the installation position of the cutting device 7. This allows the dummy bar preparation work of the continuous casting equipment 1 and the maintenance work of the cutting device 7 to be performed in parallel. As a result, the downtime of the continuous casting equipment 1 is reduced, and productivity can be improved.

[0022] Here, the segment rolls 5 need to be arranged continuously at a predetermined interval along the direction of transport of the slab in order to support, guide and cool the slab. Therefore, the dummy bar intrusion prevention device 8 of this embodiment is arranged between the last segment roll 5a and the cutting device 7, not between the segment rolls 5. That is, in order to arrange the dummy bar intrusion prevention device 8 between the segment rolls 5, it is necessary to thin out the segment rolls 5 to ensure an arrangement space, which makes it impossible to arrange the segment rolls 5 at a predetermined interval.

[0023] In the case of preventing the dummy bar 40 from entering the installation position of the cutting device 7 by the conventional continuous casting equipment, it is possible to lower the upper roll of the upper and lower rolls constituting the final segment roll 5a and place it on the path line of the dummy bar. According to this method, the dummy bar 40 that has slid down along the in-machine casting belt L1 is in a positional relationship in which it collides with the upper roll in the lowered state, so that the dummy bar 40 does not reach the installation position of the cutting device 7. However, in this method, when the dummy bar 40 that has slid down collides, there is a risk that the final segment roll 5a, which is a device used for continuous casting, will be damaged and the line will stop, and an improvement in the device not used for continuous casting has been required. On the other hand, according to the present invention, the equipment required for conventional continuous casting is not used, and the dummy bar entry prevention device 8 is newly installed, so that the risk of equipment failure described above can be suppressed.

[0024] The installation position of the dummy bar intrusion prevention device 8 is preferably at or downstream of the recovery position where the dummy bar 40 is lifted and recovered during the dummy bar preparation work. Usually, the recovery work of the dummy bar 40 is performed at a position immediately after the final segment roll 5a. In this embodiment, the dummy bar intrusion prevention device 8 is disposed on the cutting device side where it does not interfere with the dummy bar recovery work.

[0025] <Configuration of the dummy bar intrusion prevention device 8> The dummy bar intrusion prevention device 8 will be described in detail with reference to Figures 3 to 5. Figure 3 is an enlarged view of region P in Figure 1 indicated by a dashed line, and illustrates the details of the dummy bar intrusion prevention device. However, the cast piece is not illustrated. Figure 4 is an enlarged view of region Q in Figure 2 indicated by a dashed line, and illustrates the details of the dummy bar intrusion prevention device. Figure 5 is a view taken along the line AA in Figure 3, and illustrates the shock absorbing portion lowered relative to the pass line of the cutting and conveying belt L2 with a solid line, and the shock absorbing portion raised relative to the pass line of the cutting and conveying belt L2 with a dashed line.

[0026] The dummy bar intrusion prevention device 8 includes a base plate 81, a frame 82, a pair of lifting devices 83 (corresponding to "lifting mechanism"), and a shock absorbing portion 84. The base plate 81 is fixed to the floor surface of the factory. The frame 82 includes a bottom part 821 and a support frame part 822. The bottom part 821 is fixed to the base plate 81. The support frame part 822 extends upward from the bottom part 821. The lifting device 83 is fixed to the base plate 81 and the bottom part 821 of the frame 82, and supports the shock absorbing part 84 so that it can be raised and lowered.

[0027] A bottomed cylindrical housing portion 83a is formed in the pair of lifting devices 83, and a piston 831 is housed in this housing portion 83a in a state in which it can be raised and lowered in the vertical direction. The tip portion of the piston 831 is fixed to a pair of arms 841 extending from both side surfaces of the shock absorbing portion 84.

[0028] When a fluid (air, oil, etc.) is fed into the container 83a, the piston 831 is advanced, and the shock absorbing portion 84 can be raised and lowered relative to the path line of the cutting and conveying belt L2. By draining the fluid from the container 83a, the piston 831 moves toward the bottom dead center, and the shock absorbing portion 84 can be lowered from the path line of the cutting and conveying belt L2.

[0029] In this way, by configuring the dummy bar intrusion prevention device 8 with a so-called cylindrical structure, the impact absorbing section 84 can be raised and lowered without any problems relative to the pass line of the cutting and conveying belt L2 even in the usage environment of the present invention where dust from the casting may be floating in the air.

[0030] When the dummy bar entrance prevention device 8 is lowered, the upper end of the dummy bar entrance prevention device 8 is located below the pass line of the cutting and conveying belt L2. Therefore, the dummy bar entrance prevention device 8 does not get in the way when the slab is conveyed toward the cutting device 7 during continuous casting.

[0031] The shock absorbing section 84 may have a crushable structure. A crushable structure is a structure that absorbs impact energy by plastically deforming when the dummy bar 40 hits the shock absorbing section 84. The shock absorbing section 84 may be, for example, a hollow structure having a large number of hollow portions.

[0032] Structural examples of hollow structures will be described with reference to Figures 6 to 8. Figures 6 to 8 are plan views (i.e., views seen from above) of each hollow structure. A hollow structure is a structure that consists of multiple hollow parts, and adjacent hollow parts are separated by walls.

[0033] The hollow structure in Fig. 6 has a tile structure and is configured with a large number of rectangular hollow sections 84a that penetrate vertically to form the shock absorbing section 84. The hollow structure in Fig. 7 has a mesh structure and is configured with a large number of diamond-shaped hollow sections 84b that penetrate vertically to form the shock absorbing section 84. The hollow structure in Fig. 8 has a honeycomb structure and is configured with a large number of hexagonal hollow sections 84c that penetrate vertically to form the shock absorbing section 84. By making the shock absorbing section 84 a hollow structure, the wall undergoes plastic deformation when the dummy bar 40 collides, causing the hollow section to collapse, thereby absorbing the shock. In this embodiment, the opening direction of the hollow portion is the vertical direction, but the present invention is not limited to this, and it may be a horizontal direction perpendicular to the path line of the cutting and conveying belt L2. Furthermore, the end opening of the hollow portion may be closed with a plate material or the like.

[0034] Here, since the temperature of the slab transported by the table roll 6 is about 900°C, the shock absorbing parts 84 receive the heat of the slab and rise in temperature. Therefore, it is desirable that the shock absorbing parts 84 are made of a heat-resistant material (for example, an iron material).

[0035] In this embodiment, the shape of the shock absorbing portion 84 is a rectangular parallelepiped, but it may be another shape. The other shape may be a cylinder or a sphere, or may be an extruded polygonal shape (triangle, square, etc.).

[0036] In this embodiment, the shock absorbing unit 84 is a hollow structure, but the present invention is not limited to this and may have other configurations. The other configurations may be, for example, a structure in which multiple rows of suspensions are sandwiched between plates. For example, a frame supporting the shock absorbing unit 84 (a structure in which suspensions are sandwiched between plates) may be assembled on the table roll 6, and a lifting mechanism that lowers the shock absorbing unit 84 (a structure in which suspensions are sandwiched between plates) may be mounted on the pass line with an electric chain sprocket, and the shock absorbing unit 84 (a structure in which suspensions are sandwiched between plates) may be lowered to the pass line as a measure to prevent the dummy bar from entering.

[0037] Next, a description will be given of a typical example of use of the dummy bar intrusion prevention device 8. For ease of explanation, a state in which the shock absorbing unit 84 is raised relative to the pass line of the cutting and conveying belt L2 is defined as a shock absorbing state, and a state in which the shock absorbing unit 84 is lowered relative to the pass line of the cutting and conveying belt L2 is defined as a standby state. The shock absorbing unit 84 is switched from the standby state to the shock absorbing state by driving the dummy bar intrusion prevention device 8 in synchronization with the start of the dummy bar preparation work. The dummy bar intrusion prevention device 8 can be operated by outputting an operation signal from, for example, the operator's compartment. The means for outputting the operation signal may be wired or wireless. Note that the shock absorbing unit 84 may be switched from the standby state to the shock absorbing state in advance before the start of the dummy bar preparation work.

[0038] Here, when carrying out the dummy bar preparation work, a crane or the like can be used to bring in an iron plate between the segment roll 5 and the cutting device 7 as a countermeasure against the intrusion of the dummy bar 40. However, this method takes a long time to complete the countermeasure against the intrusion, and the work becomes complicated. In contrast, in this embodiment, the standby state can be switched to the shock absorbing state simply by outputting an operation signal from the operator room and moving the piston 831 upward, so that the countermeasure against the intrusion of the dummy bar 40 can be immediately implemented.

[0039] With the shock absorbing state switched to as described above, it is possible to simultaneously carry out dummy bar preparation work and maintenance work on the cutting device 7. Even if the dummy bar 40 is not guided properly and slides down during maintenance work on the cutting device 7, the shock absorbing portion 84 prevents the dummy bar 40 from entering, so that maintenance work on the cutting device 7 can be continued without hindrance.

[0040] The shock absorbing state is switched to the standby state by driving the dummy bar intrusion prevention device 8 in synchronization with the completion timing of the dummy bar preparation work. By switching to the standby state, the shock absorbing part 84 descends toward the pass line of the cutting conveyor belt L2, so that continuous casting can be started immediately. If the maintenance work of the cutting device 7 is not completed within the time of the dummy bar preparation work, the shock absorbing state may be continued until the maintenance work of the cutting device 7 is completed.

[0041] In this embodiment, the shock absorbing state can be switched to the standby state simply by outputting an operation signal from the operator room and lowering the piston 831. Therefore, continuous casting can be started immediately after the dummy bar preparation work (or after the maintenance work is completed).

[0042] (Modification) The present invention can also be applied to a multi-strand continuous casting facility having multiple strands. In this case, the dummy bar intrusion prevention device 8 may be configured to drive each strand independently, or may be configured to drive all strands synchronously. Needless to say, when driving all strands synchronously, it is necessary to ensure that the dummy bar preparation work is performed in a shock absorbing state in all strands and that continuous casting is performed in a standby state.

[0043] (Modification) In the continuous casting facility, the cast piece is formed into various shapes such as a slab, bloom, billet, etc. according to the downstream manufacturing process, but the present invention does not limit the shape of the cast piece. [Explanation of symbols]

[0044] 1. Continuous casting equipment 2 ladle 3 Tundish 4. Mold 5 Segment Roll 5a Final segment roll 6. Table Roll 7 Cutting device 8 Dummy bar entry prevention device 84 Shock absorbing part

Claims

1. A continuous casting facility including a slab production line formed of a plurality of segment rolls and a plurality of table rolls, and a cutting device that cuts the slab to a predetermined length, A dummy bar intrusion prevention device is disposed between a final segment roll disposed most downstream among the plurality of segment rolls and the cutting device, The dummy bar intrusion prevention device is provided with an impact absorbing portion that can be raised and lowered relative to a pass line in the cutting and conveying zone of the cast strip production line. The continuous casting equipment is characterized by:

2. The impact absorbing portion is a crushable structure that plastically deforms during a collision to absorb impact energy.

2. The continuous casting equipment according to claim 1 .

3. The crushable structure is a hollow structure having a large number of hollow portions.

3. The continuous casting equipment according to claim 2 .

4. The dummy bar intrusion prevention device has a mechanism for raising and lowering the shock absorbing portion relative to the pass line.

4. A continuous casting facility according to claim 1, wherein the continuous casting facility is a casting facility for casting a steel sheet.

5. A method for maintaining and servicing a continuous casting facility according to any one of claims 1 to 3, With the shock absorbing portion elevated relative to the pass line, a dummy bar preparation operation for checking the insertion and removal of the dummy bar and a maintenance operation for inspecting and repairing the cutting device are performed in parallel. A method for maintaining operation of a continuous casting facility, comprising the steps of:

6. The operation and maintenance method for a continuous casting facility according to claim 4, With the shock absorbing portion elevated relative to the pass line, a dummy bar preparation operation for checking the insertion and removal of the dummy bar and a maintenance operation for inspecting and repairing the cutting device are performed in parallel. A method for maintaining operation of a continuous casting facility, comprising the steps of:

Images